ST. LOUIS (KSDK) - You've heard the saying birds of a feather flock together, but sometimes those flocks are down right ridiculous. That's why NewsChannel 5's Heidi Glaus went out to find out the answer to Barbara O'Neil's question about why they move in unison in this week's Hey Heidi report.

"Like my buddy, he swears there were millions of birds in that flock," Michael Zeloski, a naturalist with World Bird Sanctuary explains.

You know, the packs of black birds that from a distance look more like a puff of smoke than birds in flight.

"They can be in the thousands," Zeloski points out.

The reason for their maneuvering in such masses is rather simple.

"They travel to feed mostly and they also travel to find the night roost. They want to roost together so they're all together so predators can't get them," Zeloski explains.

And flying together is well, easier.

"When one bird is following behind another it is much easier for the birds behind," Zeloski adds.

The old saying isn't necessarily true because flocks might consist of a couple of different birds.

"Often they're Common Grackles. There's also sometimes a mix of Brown-headed Cowbirds and Red-winged Blackbirds and sometimes there's some Starlings mixed in too," Zeloski says.

What you saw in the movie "The Birds" back in 1963 was none of those.

"I think they mostly used crows," Zeloski says with a grin.

When you see a large flock in your yard they're usually there to eat.

"When they go into suburban neighborhoods they're often eating acorns like Pin Oaks," he adds.

Which apparently they can swallow whole.

Here's one more fowl fact about why the females are less colorful.

"It is to be more camouflaged," Zeloski explains.

So hopefully predators don't notice them when they're laying eggs. One thing is for sure, there are certain flocks that are impossible to miss.